Marc-Adrian Napoli <marcadrian@cia.com.au> wrote:
> How can I stop linux from them swapping out? I've heard that disk
swapping
> is a big no no on a box running squid... so I assumed that if you
assigned
> all the memory to squid, it wouldn't attempt to swap out on itself.
No! Swapping is based on frequency of access to the memory. You'll have
the same number of requests with a small memory footprint or a large one -
but with the small footprint, you'll probably hit all of your memory much
more frequently than with a large footprint. Say you only use cache_mem of
4M, you might churn through the entire 4M every second. cache_mem of 500M
might take a couple minutes, so there's a higher chance of some of that
500M getting swapped out (because the OS thinks it can do better things
with that memory).
OTOH, it _is_ more efficient to serve pages out of cache_mem. So if you
have tons of memory, it probably does pay to raise it from the defaults.
I'd just be leery of raising it too far.
On the gripping hand, you might be able to tell your OS to not swap Squid,
either explicitely, or by some trick (such as telling it to never use more
than (total-squid) bytes of memory for filesystem buffers, or something of
the sort).
Later,
scott
Received on Thu Nov 11 1999 - 10:11:17 MST
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